Combined drilling and tapping machine



May 15, 1928.

1,670,287 c.- A. STICKNEY COMBINED DRILLING AND TAPPING MACHINE Filed June 30, 1924 14 Sheets-Sheet 1 Ma Q. an; flue 44013 aw. hda;

May 15, 1928.

C. A. STICKNEY COMBINED DRILLING AND TAPPING MACHINE May 15, 1928. 1,670,287 c. A. STICKNEY COMBINED DRILLING AND TAPPING MACI:IINE

May 15, 1928.

C. A. STICKNEY COMBINED DRILLING AND TAPPING MACHINE Filed June 50, 1924 14 Sheets-Sheet 5 May 15, 1928. 1,670,287

c. A. STICKNEY I COMBINED DRILLING AND TAPPING MACHINE Filed June 30, 1924 14 Sheets-Sheet 6 May 15, 1928.

C. A. STICKNEY A COMBENED DRILLING AND TAPPING MACHINE Filed June 30, 1924 14 Sheets-Sheet 7 Jvwewtoz May 15, 1928.

C. A. STICKNEY COMBINED DRILLING AND TAPPING MACHINE Filed June 30, 1924 14 Sheets-Sheet 8 May 15, 1928.

C. A. STICKNEY COMBINED DRILLING AND TAPPING MACHINE Filed June 30, 1924 14 Sheets-Sheet 9 May 15, 1928. c. A. STICKNEY ACOMBINED DRILLING AND TAPPING MACHINE 14 Sheets-Sheet 10 Filed June 50, 1924 Wuuuuu 1i;

a E MN avwenkoz I ma.

May 15, 1928.. 1,670,287

C. A. STICKNEY COMBINED DRILLING AND TAPPING MACHINE Filed June 30, 1924 14 Sheets-Sheet 12 1 PQ "D 2 w S N H Q Q M b o p "J I, m m x F Q Q: 5-, fi h) a Q l \1 HQ\ :3 9 v Q o EF Fi i- :1 n

o "L- N U mqmawbw 14 Sheets-Sheet 13 C. A. STICKNEY COMBINED DRILLING AND TAPPING MACHINE Flled June 30, 1924 May 15, 1928.

anvcyxtoz 1 COMBINED DRILLING AND TAPPING MACHINE Filed June 30, 1924 14 Sheets-Sheet 14 awwemtoz Patented May 15, 1928.

UNITED STATES PATENT OFFICE.

CHARLES A. STICKNEY, OF ROCKFORD, ILLINOIS, ASSIGNOR TO THE NATIONAL AU- TOIATIC TOOL COMPANY, OF RICHMOND, INDIANA, A CORPORATION OF INDIANA.

COMBINED DRILLING AND TAPPING- MACHINE. I

Application filed June 30, 1924. Serial No. 723,164. g

This invention relates to a combined drilling and tapping machine; that is a machine tool provided with a plurality of spindles and adapted siimiltaneously to perform drilling and tapping operations.

A machine-tool of this nature may be used advantageously for quantity production wherein successive pieces of work require the drilling and tapping of holes in a predetermined arrangement. In the operation of this machine-tool the operator sets up the work on the work-table and performs the drilling operation in the usual way just as though no tapping mechanism was present. lVhile the drilling is being effected a previously drilled piece being tapped automatically without any attention or effort on the part of: the operator. After the tapping operation is completed, the work is again brought to the operator for removal from the work-table. Thus it will be seen that inasmuch as only one set-up is required for the two operations and as no additional time is required for the tapping o eration, production is increased substantially 100 per cent, as compared with pcrforniing the same operations in separate drilling and tapping machines,without any additional operative cost, or effort on the part of the operator. Furthermore one combined drilling and tapping machine requires substantially less operating floor space than do two separate machines, which likewise effects a substantialsaving in factory installation.

An object of this invention is to provide a combined machine having two separate and distinct sets of spindles of which one set is preferably rotated in a single direction and is adapted particularly for drilling and the other set is adapted to be rotated in both forward and reverse directions and may, therefore, perform either drilling or tapping operations, the reverse rotation serving to unscrew the taps from the work after the holes have been tapped.

In some classes of work it is necessary that all of the holes be tapped whereas in other work only certain ones must be tapped. It is therefore an object of this invention to provide a combined drilling and tapping machine in which a plurality of holes may be drilled simultaneously and in which any or all of such holes may be tapped in a A furt ier objectis to provide automatically acting means for transferring the work from a position in which it is acted on by one series of tools to a position in which it will be acted on by the other series ottools in the next succeeding operation of the machine. This object may be attained. by providing a rotary work-supporting table together with power actuated means for rotating the table between successive operations.

A still further object of the invention is to provide, in a combined drilling and tapping machine, a single source of power and improved means operated thereby for rotating all of the tools and for feeding them into and out of the work.

Another object of the invention is so to co-ordinate the tool rotating and feeding mechanisms that the latter will always be maintained proportionate to the former, whereby the tapsand drills will always be fed into the work at a speed commensurate with the most efficient speed of rotation of the taps for any desired operation.

A further object is to provide an improved form of rapid feed to bring the tools into contact with the work and to remove them therefrom after a drilling or tapping operation.

Another object of this invention is to rovide, in a machine of the character descri ed, automatically acting means for reversing the direction of rotation. of the taps at an increased speed after they entered the Work a predetermined distance and sin'mltaneously therewith changing the direction of feed of the drill-head.

A further object of the invention is to provide an intermediate speedup-feed foe the head, and to render said feed effective during the reverse rotation of the taps to elevate the head at the same speed that the taps are withdrawn from the work.

Still another object is to provide automatically acting-means for controlling all of the various trains of mechanism of a combined drilling and tapping machine viz., a rapid power-teed, a slow power-feed, an intermediate speed-feed, drill and taprotating mechanisms and a tap reversing mechatool-head is slidably mounted.

the present invention. the'bridge of the machine showing the drive. and feed mechanisms, the cap and coverof the objects hereinbefore enumerated and so to construct the frame work therefor that the machine will be capable of withstanding extremely heavy loads without material deflectiomand upon which the tool-head may -be more rigidly supported than has heretofore been possible.

This object is attained by providing a heavy base upon which are rigidly supported two 'ponderous columns upon which the The tops of the columns are preferably tied together by means of a heavy bridge which also serves to support the weight of the tool'head and to house substantially all of the mechanism for elevating and depressing the tool-head and forrotating the spindle drive-shafts.

'Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom in connection withlthe annexed drawings.

To enable others skilled in the art so fully'to apprehend the underlying features hereof that they may embody the same in the various ways contemplated by this invention, drawings depicting a preferred typical con struction have been annexed as a part of this disclosure and, in such drawings. like characters of reference denote corresponding part-sthroughout all the views, of which:

Fig. 1 is a sideelevation of the combined drilling and tapping machine embodying Fig. 2 is a plan of platebeing'omitted. Fig. 3 is a longitudinal vertical section substantially along the line 3-3 of Fig. 2. Fig. tiis an enlarged vertical section of the left end of Fig. 2. Fig. 5 is a plan of Fig. 4. certain of the mechanism being omitted for the sake of clearness. Fig. 6 is an enlarged vertical section of the opposite ends of the bridge showing,'at the right, the rapid drive from the power shaft to the feed-shaft, and at the left the drive from the power shaft, through the cycle-clutch to the can't-shaft. Fig. *7 is an enlarged transverse section throughthebridge on the line 7-7 of Fig. 2. Fig. 8 is a gear lay-out showing the means for transmitting power from the main line 17 -17 of Fig. .15.

power-shaft to a cam-shaft, from the powershaft to a slow spindle drive-shaft and from the slow spindle drive-shaft to a feedshaft, all later to be described. Fig. 9 is an enlarged section of one of the friction clutches together with its actuating mechanism. Figs. 10, ll and 12 are front, end, and plan views, respectively, of a cyclecontrolling mechanism later to be referred to. Fig. 13 is a horizontal section on the line 1313 of Fig. 10. Fig. 14 is a. vertical section on'lhe line l l-l4 of Fig. 13. Fig. 15 is an enlarged front view. partly in section, of the actuating means for the cyclecontrol mechanism. Fig. it} is a side view, partly in section of the parts shown in Fig. 15. Fig. l? is a horizontal section on the Fig. ii) is a sectional view of an epicyclic gearing. forming a part of a. feeding mechanism later to be described. Fig. l9 is a section on the line l9l$) of Fig. 18. Fig. 20 is a central vertical section of the work-supporting table. Fig. 2U is a. detail section on the line (1-u. of Fig. 20 showing, an intake port for fluid under pressure. Fig. 21 is a section substantially on the line 2.l2l of Fig. 20. Fig. 22 is :1 diagrammatic representation of the nn-chanism for effecting the rapid up and down feeds of the head. Fig. 23 is a diagrammatic representation of the means for rotating the spindle drive-shafts when both of the sets of spimlles are used for drilling. Fig. i l is'a. similar view of the tap-spindle rotating mechanism. Fig. 25 is a diagrammatic representation of the tap-spindle retating mechanism together with the means for effecting slow downward feed of the head when lapping. Fig. 26 is a similar view showing, in full lines, the means for effecting the tap-spindle reverse drive, the intermediate spced upfced for the head and the means for rotating said spindle and the slow-down feed fol-the head when the machine is used for drilling only. Figs. 27 and 28 are diagrammatic represcntations in side and front view, respectively, of a hand feed for the head. Fig. 2.) is a diagrammatic view illustrating the initial flow of tluid under pressure for rotating the. bed of the work-table. Fig. 30 is a similar view illustrating the flow of fluid in the second stage in the operation of rotating the bed; and Fig. Ell is a similar view illustrating the flow of fluid when fluid is being exhausted from the various cylinders.

l'tel'erring more particularly to the drawings the invention is disclosed, in its preferred form. as embodied in a combined drilling and tapping machine comprising a base A upon which are mounted upright columns 0 and 1). Upon the upper ends of these columns is supported a. bridge B which carries suhstzmtiall all of the actuating mechanism of the machine.

A tool-head H, carrying two sets of rotatable spindles s and s, is supported from the bridge and is vertically movable between the columns C and D by means of feedscrews S and S threaded through nuts N and N harried at opposite sides of the tool-head and tracking guideways formed in the columns. These screws are rotated by mechanism carried by the bridge as will later be described.

Power to operate the various trains o't mechanism enters the machine through a power shaft 1 journaled lengthwise of the bridge in bearings l, 2, 3 l, 5 and 6 and adapted to be rotated by anysuitable means, as for example a pulley 1: or other prime-mover. From the shaft l power is taken, by mechanism later to be described, to rotate the two spindle drive-shafts E2 and 3 which in turn act to rotate the drill spindles s and tap-spindles s respectively at variable speeds through the action of suitable change-gears located in a gear-chest 4: carried by the head H. Inasmuch as means for operatively connecting the spindles .s' and s with their drive-shafts 2 and 3 and the change-gear mechanisms for varying the speed of rotation of the spindles lorm no part of the present invention, detailed illustration and description thereof is deemed unnecessary.

While this machine will be described as being adapted primarily for the combined operations of drilling and tapping it .is to be understood that it may also be used as a straight drilling machine, in which case both sets of spindles Will be titted with, drillpoints and the reversing mechanism for the one set will be rendered ineffective.

Pie-supposing that one piece of work has been set up on thework-table and drilled, the operation of the machine when used as a combined drilling and tapping machine is as follows:

The operator sets up a second piece of work on the table T and, through means later to be described, causes the table to rotate 120 degrees. This rotation places the new piece of work in position to be operated on by the drills driven from the spindle drive-shaft 2 and simultaneously therewith'places the previously drilled piece in position to be operated on by the taps driven from the spindle drive-shaft 3. Then, by manipulation of a suitable handlever, carried by the head, a cycle-controlling mechanism (later to be described) is tripped into action and wauses a partial rotation of a cam-shaft. The cam-shaft carries cams which, in this partial rotation actuate two clutches, one of which disconnects a handfeed for the head and the other of which puts into action a rapid feed to quickly lower the head to bring the tools into contact with the work. As the tools approach the intermittently rota-ted cam-shaft X,

work the spindle-rotating mechanism is put into action, the rapid feed is thrown out and a slow power feed is thrown in. This slow feed continues until the drilling and tapping is completed, at which time the slow downfeed is stopped, the directionot rotation of the taps is reversed, an intermediate speed up-feed is put into action to elevate the head at the same speed that the taps are withdrawn. \Vhen the taps have cleared the work, the slow up-feed is thrown out, the rotation of the drill-spindle is discontinued, and the rapid up-teed is made effective to rapidly elevate the head and the tools carried thereby. As the head reaches its u permost position the rapid up-ilced and the drill and tap-spindle rotating mechanisms are thrown out and the hand-feed is again connected to permit manual adjustment of the head.

. The mechanism for producing these various movements and operations is n'e'lereably carried by the hollow bridge B and located partially within a cap E closed at its upper side by a cover-plate F. The various trains of mechanism will .now be described in detail in their order of operation.

Rapid up and rapid (101.0% feeds for fire head.

Vithin the cap E and parallel with the power shaft 1, there is -journaled, in bearings a, a, a, and a a reversely rotatable :t'eed-shai't a to which are secured bevelpinions a and a These pinions mesh respectively with bevel-gears a and a iixed to the iced-screws S and S. The shaft a? carries, intern'iediate its ends, two normally ineffective :t'riction-clutches, viz. a rapid down-feed clutch a and a rapid up-iteed clutch 1/ either of which may be rendered effective to rotate the shaft a These clutches are, in the normal operation of the machine, operated alternately by means ol a fork a. secured upon a rod i journaled at its opposite ends, in the bridge The rod (4 also carries an arm a supporting a stud or roller (6 which tracks a eam-grove a formed in a cam-cylinder a." fixed to an journaled in bearings w carried by the bridge.

Power, to rotate the 'ieed-sha'l't a counterclockwise, as viewed from the right end of the machine to elevate the head H, may conveniently be taken from the power shaft 1 by means of a gear u. thereon which drives a gear a journaled in a bracket (1 secureijl to the bridge. (See Figs. 6 and 22.) The gear a in turn drives a gear a which meshes with and drives a gear 1!. carried by one portion of the rapid lip-feed clutch (1.. Thus when the clutch a made cl"- fective by the action of the cam-groove a the feed-shalt (6 will be rotated in a direction opposite to that of the power shaft and at; approximately three-fourths its speed, thereby causing the screws S and S to elevate the head.

The rapid down-teed is effected by the cam-groove a" shifting the fork a in the opposite direction thereby ctuating the friction-clutch a Rigidly connected with the gear a is a gear a which meshes with a gear a secured upon one end of a revi-n'sely rotatable shaft a. journaled in the bridge. Upon the opposite end of the shaft (1' there is secured a gear a? in mesh with a gear 0? carried by a portion of the clutch 11 Thus when the clutch u made ett'ectivc the shaft (1 will be rotated in the. same direction as the power shaft and the screws S and S will feed the head H downwardly. In the latter drive the gear (1 will also rotate but inasmuch as the clutch (1 is then disconnected, this will be merely idle rotm tion.

Drill-spindle rot/(ling mechanism.

Journaled co-axially with the power shaft 1 and adapted, at certain times, to be rotated therewith by means of: a trietimi-clutch I, is a bevel-gear If permanently in mesh with a like gear I) secured upon the lower end of a stub shaft 6'. (See Figs. 3, and The clutch I) is actuated by a lever b pivoted at b and having one end in engagement with the clutch and carrying at its opposite. end a pin or roller Z) which tracks a cam-groove (2 formed in a cameylinder I)" secured upon the shaft: X. The shaft 11 is journaled in a standard 71' fixed within the bridge and carries at its upper end a pinion I) which. drives a gear I) recured upon the upper end of" the drill-spindle drive-shaft 2. Thus when the frictioncluteh b is rendered etl'cctive by its controlling cam b the shaft 2, and thereby the drill-spindles, will be rotated.

As hcreinbet'ore stated this machine may be used solely for drilling, that is drill points may also be fastened in the spindles s rotated from the drive-shalt 3. When the machine is used in this manner the spindle drive-shaft 3 is driven from the power shai't by means of a bevel-gear 0 carried by a triction'clutch i') similar in construction to the clutch I). This clutch is controlled and actuated by a cam b formed in a cane cylinder 7) secured upon the shaft X, through the medium of a clutch-shifter The bevel-gear 7' meshes with and drives a similar gear I) tixed upon the lower end of a stub-shaft b journaled in a standard 20. The upper end of the shaft 0" carries a pinion b" which drives a gear 22 fixed upon the upper end of the drive-shaft 3.

It is to be understood that when the machine is used for both drilling and tapping the clutch 71" is maintained inetl'ective and therefore the drive-shaft is not operated as described in the preceding paragraph but by means later to be described.

Tap-spindle forward (Zr-ire.

When the spindles s are used for tapping the clutch b is maintained inetl'ective and the spindle drive-shaft 3 is rotated at a reduced rate as follows. (See Figs. 2, 3, 5 and 24.)

Secured to the power-shaft 1 and adjacent one end thereof is a smallgear c which constantly drives a large gear fixed to a shaft 0 journalcd in bearings c and c carried by the bridge. Also secured to the shaft 0 is a small gear 0 permanently meshing with a large gear 0 carried by one portion of a normally inetl'ectiive friction-clutch 0''. At a predetermined time in the cycle. ol operation this clutch is rendered ell'ectire to drive a shaft 0, by a clutch shit'ter through the action of a can't-groove 0 formed in a cam-cylinder (1, also carried by the shaft X. Secured to the shaft 1: is a gear c in mesh with a larger gear 0 t'nzed upon ash-aft c journaled in hearings c" and 0". The shaft 0" which forms a part of the tap forward-drive mechanism also forms a part of a slow power-teed for the head H, as will later be described. By utilizing this shal't as a teed-drive shaft, the slow power-feed is always maintained proportionate to the speed of rotation ofthe taps.

The shaft 0 carries at its forward end a bevel-gear c which drives a like gear e" secured upon a stub-shaft c journaled in the standard 20. The shaft; 0" also carries a pinion c" which drives the gear 22 tixed upon the upper end of the spindle drive-shaft 3 to rotate the taps inaforward direction.

Drill and tap power iii-feral.

A slow power-feed is provided to move the head H downwardly to feed the drills and taps into the work. As hereinbefore stated power to operate this feed is taken from the shaft 0" which, when the machine is used simultaneously. for drilling and. tapping, is rotated from the main power shat't 1 through gears c, 0-, shaft 0, gears c 0 clutch a and gears c and 0". (See l igs. 2, -it, 8 and. 525;) The shalt c earries, at its extreme rearward end, a gear (I which drives a gear d secured upon one end of a short shaft d journaled in a bearing (1 provided by the bridge. The o jipositc end of the shaft (1 -arries a gear (1 which meshes with and drives a larger gear (1 on a. suitable shaft (1 Fixed to the gear (1" is a smaller gear d permanently in mesh with a larger gear (1 carried by one portion of a normally inell'ectivc friction-clutch (Z. This clutch, at certain times is rendered efi'ective by means of a clutch-shifter d' llltl having a portion provided with a pin or roller which tracks a cam-groove (il formed in a cauncylinder d secured upon the cainshat't X. hen the clutch is thrown into action by the n a" the gear if" is caused to rotate the d-shat't a? carrying the bevel-pinions (0 ant a which mesh with like a. and a l'iX-cd to the upper ends 03' the 'tccttscrcn's ifi and H, rcluiectively. llront the l'oregoing it will be observed that power is taken from the tap-rotating shaft 0 at whatever speed that shaft is rotated and, through suitable reductiongears, this speed is gradually reduced to drive the iced-screws at a relatively low speed but always proportionate to the speed of the tap-rotating shaft.

When the machine used solely for drilling, power to rotate the teed-shaft a flows from the power shaft 1. through a partially different train. (See Figs. 2 and 26.) In this instance the spindle drive-shattt 3 is driven from the power shaft 1 through gears b, 7), shaft 6 and gears l)- and 22, and power is transmitted from the gear 22 through geai 's 0", c and a to the shaft 0 which it will be perceived, will be rotated in the same direction as when tapping but at a very much higher speed, to wit, the speed of rotation of the drive shaft .l. \Vith the shaft o driven in this manner the gear (1" is shifted inward on its shaftto disconnect it from the gear al and to connect; it with a gear d forming a part of an epicyclic reduction gearing (later to be described) which efi'ects a speed reduction equal to the reduction effected by the gears c c 0. 0 0 (1 etc., when the power is being transmitted therethrough. From the gear (Z the power to rotate the teed-screws is transmitted thereto as previously de scribed.

The epicyclic gearinglnay he of conventional form and may COYHPI'lSQ an eccentric d fixedto the shaft 0' as by means ot a key (1. (See Figs. 1.8 and 19.) Loosely journalcd upon a bushing d surrounding the eccentric (1 are gears cl and d of which the torniermeshes with an internal gear (7 formed in a falne d lixed to the bridge B. The gear d likewise meshes with an internal gear (1 loosely journaled on the shaft 0" and upon which is keyed the gear (7. Thus rotation of the shaft 0 will. due to the difference in ratio between the gears d and 1. and their refive unites rotate the gear (Z at a materially reduced ate in a well-known manner.

Tap-spindle relic/ac drive.

\Vhcn the taps have entered the work a.

prodetcrinined distance the earn 0 actuates the ClHtClbHhlftQI c which then permits the tinned. At that instant the downward feed ol the head is also discontiruiedand an upward feed is begun to raise the head H and the tools carried thereby.

To permit withdrawal of the taps trou'i the work it is necessary that they be rotated in a reverse direction to unscrew them from the holes that they have just previously tapped. This reversorotation may be at a substantially greater rate than the forward rotation of the taps and may conveniently be etlectcd by mechanism now to be described. (See Figs. 2, 3 and 26.)

Coaxial with the power shaft 1 is a normally ine lfective friction clutch c to which secured a bevel-gear a permanently in mesh with the bevel-gear I) dian'ietrirally opposite the gear 6 hen the forward rotation of the tap has been stopped the clutch e is caused to lock the gear a to the power shaft 1 which, through gear I), shaft b pinion I) and gear 22 cause re verse rotation in the drive-shaft 3 and there by in the tap-spindles s.

It is to be noted that if the drive-shaft 1 is rotated at say 500 R. P. M. in the forward rotation of the taps the shaft 0 will be rotated at approximately 40 R. P. M., whereas when the taps are reversed as just previously described the shaft 0 will be rotated at substantially the same speed as the drive-shaft. Then, as the connections from the shaft 0 to the feed-screws S, S, are the 5511110 in both instances it follows that the slow tip-teed of the head will be sub stantially faster than its slow-down feed. This increase in feed is proportionate to'the increase in the speed of rotation of the taps when being reversed and withdrawn from the work.

The friction-clutch e preferably actuated by means of a clutch-shifter 6 connected at one end to the clutch and carrying, at its other end, a roller a tracking a camgroove 6" formed in a cam-cylinder e secured upon the shaft X.

late/viierliate-s need tip-feed for the head.

Simultaneously with the throwingin of the tap-reverse-dr.ive an intermediate speed lip-teed tor the head. is put into action to elevate the head at the same rate that the taps are withdrawn. iliroin the work due to their reverse rotation. This is accomplished by disconnecting the forward-feed clutch 0 and reversel y rotating the feed-drive shaft 0" "from the spindle drive-shaft 3 through gears 22, 0 shaftc and gears 0"" and 0 (see Fig. 26). This reverse rotation of the shaft 0 is transmitted to the ilieed-sha'lit (/f and then to the feed-screws S and S as previously described for the slowdown feed except that direction of rotation in all of the parts is reversed and thereto is faster due to the difierence in ratio of the power feeds are ineif'ective.

gears between the shaft 1 and the shaft 0 When the taps have cleared the work the clutch e is released and the rapid up-feed clutch a is actuated to cause rapid elevation of the head.

Hand-feed. for the head.

For certain purposes and at certain times, such as when initially setting up a particular class of work, it is desirable to have the head H under manual control. To this end there is provided a hand-feed by means of which the head may be raised or lowered at the will of the operator whenever the (See Figs. 1, 5, 27 and 28.)

J ournaled in the column C is a short shaft 7" which carries at one end a hand-wheel f and at the other end a bevel-gear f. This gear drives a similar gear 7' secured upon the lower end of an upright shaft 7'' which carries at its upper end a bevel-gear f permanently in mesh with a gear 7" fixed to one end of a horizontal shaft 7'' journaled in the bridge. The opposite end of the shaft 7' carries a worm f" which drives a worm wheel 7" forming: one element of a gear-unit f loosely journaled on the shaft (1 The gear-unit also provides a gear f" which drives a gear f carried by one element oi a friction-clutch f carried by the feed-shaft a". This clutch f is actuated at certain times. to lock the gear f to the feed-shaft, by the clutch-shifter (8 which also actuate-s the slow power-feed clutch (1 as previously described. Thus when the cam 1i" causes the clutch-shifter (Z to be moved toward the right as viewed in Fig. 2, the hand-feed is made efifective.

F w ction-clutc/z as.

All of the l'rietion-clutches viz a), a, I), b, c. al e and f are substantially the same in construction and it is therefore deemed sufficient to illustrate and describe only one in detail. Fig. 9 shows in longitudinal section the tap-reversing clutch e which may be used as representative of all. of the clutches, certain of them being diiiercnt only in the type of gear supported thereby.

These clutches preferably comprise an in ternal driving element 50 secured to its driving shaft as by means of a key 51 and an external driven-element 52 loosely journaled on a bushing 53 co-axial with the shaft. The element 52 is formed with a hub 54 upon which is secured, as by key 55, a gear as c. In certain of the clutches the hub 54 carries a spur-gear instead of the bevel-gear 0 The driver 50 is formed with a plurality of external ribs or splines 55 which interfit with similar splines formed within circular friction-plates 56 whereby the plates are caused to rotate with the driver 50. A similar series of plates 57 are driven by internal ribs 58 formed in the part 52. Intermediate the overlapping portion of the plates .36 and 57 are friction-washers 59 one of which bears against an annular flange (it), secured at one end of the driver 50. Slidably secured to the opposite end of the driver 50 is a clutchring 61, adapted to be shifted axially of the shalt by a clulclrshifter as 0 having one arm engaging a shiitable spool 62 slidably mounted co-axially with the shaft. The opposite arm of the clutch-shifter carries a roller as c which tracks a canrgroove as a" formed in the cam-cylinder as c" slidably secured to the shaft X as by a spline 6". Intermediate the spool (32 and the clutchring 61 is an anti-friction thrust bearing til which when the arm 6 is shifted toward the clutch, forces the clutch-ring toward the fixed flange (30 thereby causing the washers 59 to lock together the plates 56 and 57 and thereby the driving-element 5t) and the driven-element. 52.

The cam-cylinder c is splined to the shaft X and is normally maintained in contactwith a fixed collar by a heavy coil-spring G6 surrounding the shaft X and located intermediate the cam-cylinder and a fixed collar 67.

The operation of the clutch is as follows: Revolution of the cam-cylinder c", in the direction of the arrow, will first move the roller 0" to the left. and therefore the spool 62 will be moved to the right until the 'as-:hers 59 are fully compressed and the parts 50, and 52 are securely locked together. Inasmuch as the lower arm of the clutchshifter is held against further movement toward the clutch a further rotation oi the cam-cylinder will cause said cylinder to be moved to the right on the shaft X against the pressure of the spring 6(3 until the full throw of the cam-groovc a" has been utilized. This maintains the friction-clutch under heavy spring-pressure until a further rota tion of the cam-cylinder 0" causes the roller to ride down the cam-groove 0", which first permits the cylinder 6 to be moved lengthwise of the shaftby the spring (36 until it contacts with the fixed collar 65 and then to release the pressure on the friction-clutch.

It is to be noted that the cams formed in the, cam-cylinders (1," and (1 are each adapted to operate two friction'clutches and therefore the cam-cylimlcrs are maintained between opposed springs (36 and (it? which permit the cam-cylinders to yield in either direction dependent upon which clutch is actuated.

(Witch fllrlfllU-Olbf.

As previously stated this machine may be used for the combined operations of drilling and tapping or it may be used for drilling illl 

